CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance (in shares) at Dec. 31, 2013		53,926,525
Balance at Dec. 31, 2013	$ 640,133	$ 539	$ 493,279	$ 146,199	$ 116
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		147,163
Exercise of common stock options	1,105	$ 1	1,104
Employee stock purchase plan (in shares)		207,805
Employee stock purchase plan	5,253	$ 2	5,251
Stock Repurchased and Retired During Period, Shares		(3,359,604)
Stock Repurchased and Retired During Period, Value	(100,048)	$ (33)	(31,194)	(68,821)
Stock-based compensation expense	17,246
Vesting of restricted stock units and restricted stock awards (in shares)		464,804
Vesting of restricted stock units and restricted stock awards	(6,497)	$ 5	(6,502)
Tax deficiency from stock-based compensation	4,718		4,718
Fair value adjustment of derivatives, net of income tax	86				86
Translation adjustments	(4,772)				(4,772)
Net income (loss)	77,184			77,184
Balance (in shares) at Dec. 31, 2014		51,386,693
Balance at Dec. 31, 2014	634,408	$ 514	483,902	154,562	(4,570)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		329,502
Exercise of common stock options	3,472	$ 3	3,469
Employee stock purchase plan (in shares)		204,401
Employee stock purchase plan	$ 5,293	$ 2	5,291
Stock Repurchased and Retired During Period, Shares	0	(89,174)
Stock Repurchased and Retired During Period, Value	$ (3,819)	$ (1)	(1,173)	(2,645)
Stock-based compensation expense	23,471
Vesting of restricted stock units and restricted stock awards (in shares)		398,850
Vesting of restricted stock units and restricted stock awards	(8,823)	$ 4	(8,827)
Tax deficiency from stock-based compensation	$ 6,551		6,551
Stock Issued During Period, Shares, Acquisitions	794,700	794,700
Stock Issued During Period, Value, Acquisitions	$ 30,183	$ 8	30,175
Fair value adjustment of derivatives, net of income tax	122				122
Translation adjustments	(3,714)				(3,714)
Net income (loss)	$ 97,650			97,650
Balance (in shares) at Dec. 31, 2015	53,024,972	53,024,972
Balance at Dec. 31, 2015	$ 784,794	$ 530	542,859	249,567	(8,162)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)		185,484
Exercise of common stock options	2,251	$ 2	2,249
Employee stock purchase plan (in shares)		242,303
Employee stock purchase plan	$ 7,507	$ 2	7,505
Stock Repurchased and Retired During Period, Shares	(1,133,553)	(1,133,553)
Stock Repurchased and Retired During Period, Value	$ (43,091)	$ (11)	(11,885)	(31,195)
Stock-based compensation expense	26,559
Vesting of restricted stock units and restricted stock awards (in shares)		397,182
Vesting of restricted stock units and restricted stock awards	(7,160)	$ 4	(7,164)
Tax deficiency from stock-based compensation	2,739		2,739
Fair value adjustment of derivatives, net of income tax	0
Translation adjustments	(1,861)				(1,861)
Net income (loss)	$ 97,201			97,201
Balance (in shares) at Dec. 31, 2016	52,716,388	52,716,388
Balance at Dec. 31, 2016	$ 868,939	$ 527	$ 562,862	$ 315,573	$ (10,023)